Fiat and Cummins in court

ShinerBock wrote:

otrfun wrote:
Very fine dirt and debri flows around the fuel door while driving. Black residue tends to collect around the green base of the capless assembly in between fillups on my truck---no doubt this is dirt attracted to the minor diesel overspill during every fillup. Needless to say if collects there, what's to stop it from collecting elsewhere?

As far as I can tell there is no air-tight gasket on the 1st flap. Over time the simple movement of air laden with very fine dirt and debri can easily flow through and around the 1st flap down to the 2nd flap. Again, the sticky diesel fuel residue left after refueling will only hasten the collection of fine dust and dirt inside the area between the 1st and 2nd flap.

Yes, the 2nd flap has a gasket (noted in red) that prevents contaminants from falling down the fuel channel when one is not refueling. However, when the fuel nozzle is inserted for fueling purposes the 2nd flap folds down (along with any potentially collected surface contaminants), completely exposed, inside the fuel channel.

Granted, I can see how some would dismiss this as a minor, insignificant risk---which it very well may be.

However, until I read something more definitive and objective in terms of the actual risk, I've elected to use an aftermarket cap with an air-tight o-ring which negates any chance of any contaminants (airborne or otherwise) from flowing down and potentially collecting inside this cavity while driving.

The image I posted was of Toyota's capless system that they have been using for years. I could not find a diagram of the Ram's system, but I just wanted to show the basic workings of it. The Ram system is somewhat different and does address some of what you state here.

The one thing I find very humorous about this is that everyone is getting worried over the cappless system of the Ram's yet the Cummins is the only one of the three that does not have a fuel contamination issues.

Yup, I noticed the exterior portion in the image you posted was quite a bit different from the Ram.

For those of you who have owned (or operated) a number of diesel trucks, calculating the risk of fuel contamination is probably an easy process. FWIW, my '16 Ram 3500 Cummins is my first ever diesel. As such, I'll be playing it much more cautious until I get more confident with exactly how the various fuel contamination risks play into things in the realworld. In any case, very good to hear the Cummins is not prone to fuel contamination issues!